Is \(^{40}\mathrm {Mg}\) a Borromean Halo Nucleus? A Case Built on the Electric-dipole Response

We investigate the low-energy electric-dipole response of \(^{40}\mathrm {Mg}\) using a \(^{38}\mathrm {Mg}+n+n\) three-body model. This model is implemented using a three-body hyperspherical formalism with an analytically transformed harmonic oscillator basis. In this study, two different neutron–neutron interactions are considered: a scalar Gaussian density-dependent central potential and a more realistic finite-range potential which includes central, spin–orbit, and tensor components. We examine how the electric-dipole response is affected by the choice of the interaction. Abstract Published by the Jagiellonian University 2026 authors